This invention relates to a mechanism for allowing a plurality of blood bags as connected by connection tubes to communicate with each other.
Upon reference to a blood transfusion, it is noted that the age in which whole blood was used to perform a blood transfusion is gone; and presently in order to make an effective use of blood it is separated into components to conduct, for each patient, an appropriate component blood transfusion. Under these circumstances, there has been reported a so-called multiple bag which is integral, closed and sterile-sealed, and may be manipulated wholly from outside itself and in which a plurality of soft plastic-made blood bags are mutually connected by means of connection tubes. This multiple bag is used, for example, to collect whole blood into a blood collecting bag and thereafter subject the collected blood to centrifugation for separating it into two parts--platelet-rich plasma and red blood cell and transfer the upper layer of platelet-rich plasma into a smaller bag through the connection tube, thereby to effect the two part-separation, or is used to subject the platelet-rich plasma to a further centrifugation for separating it into two parts--blood plasma and blood platelet and transfer the upper layer of blood plasma into a still another smaller bag through the connection tube, thereby to effect the three part-separation.
Now, it is necessary to prevent, when the blood is subjected to centrifugation, any inseparated blood from being scattered to the interior of the connection tube. This is because the inseparated blood remaining in the connection tube, upon transfer of, for example, the separated platelet-rich plasma into the smaller bag, is mixed with the plasma causing it to be impure. In the prior art, therefore, a thin film is provided beforehand at that portion of the connection tube interior which is in the proximity of the blood collecting bag, thereby to cut off the communication between the blood collecting bag and the smaller blood bag, and, after the blood has been subjected to centrifugation, this thin film is broken to render said communication effective, thus to transfer the separated plasma into the smaller blood bag. FIG. 1 illustrates this example. A reference numeral 1 denotes the connection tube for connecting the blood collecting bag to the smaller blood bag, said connection tube being partitioned by the thin film 2. Within the connection tube is inserted a breaking needle 3 for breaking the thin film (see FIG. 1A). Upon blood transfer, the breaking needle 3 is moved from outside of the connection pipe 1 to break the thin film, thereby to render the communication between the blood bags effective (see FIG. 1B).
The blood bag-communication mechanism using the above-mentioned thin film has the drawbacks that it presents difficulties in performing its communication operation and is hard for a beginner to handle and further is troublesome to manufacture.